F Con Vpro had 32 X 32 bit and the best part is, It have self-tune features which after about 6months of daily driving, wear and tear of an engine occurs.
Means, a very minor of previous tuning may not match.
All u need is just plug in a A/F sensor and attach it to the V pro and drive it for few days.
It will let the V pro to learn the engine and self tune your ECU.
While f con V only have 16 X 24bit(if not minstaken). and it doesnt have self tune features.And it doesn't have few features of V pro such as "pro start" for drag use.
Thats all i know. I may be wrong too. I'm not an expert.
Also, don't simply listen to anyone that claims that they are good in tunning this.
cos wrong tune may harm your engine. Watch and survey for their tunning history. Collect all their good and bad experience. Then only send your car in.